The invention pertains to the treatment of gastroesophageal reflux disease (GERD).
GERD is a major health problem in the United States and worldwide. It affects tens of millions of people and costs billions of dollars to treat. GERD is the reflux of gastric contents from a stomach into a lower area of an esophagus. The gastric contents include acid secreted by the stomach which causes discomfort and eventual damage to an inner lining of the esophagus if left untreated.
The gastric contents are normally prevented from entering the esophagus by a lower esophageal sphincter (LES) mechanism. The LES is a physiologic, non-anatomic area involving the lower 3 centimeters of the esophagus and like other smooth muscle sphincters in the body, anal or urinary, it is tonically contracted to prevent reflux. A healthy LES opens for a brief period of several seconds in response to swallowing to allow the passage of food. It then quickly regains its tone when the food has passed.
GERD occurs when the sphincter mechanism of the LES fails to work properly. Generally, GERD takes one of three forms: (i) complete weakness of the sphincter musculature in response to a hiatal hernia or an intrinsic weakness that occurs commonly resulting in free reflux, which is poorly understood; (ii) partial weakness of the sphincter that allows reflux when stressed such as a Valsalva maneuver; or (iii) transient or sudden inappropriate relaxation of an otherwise normally toned sphincter.
Treatment of a weakened or inappropriately relaxing sphincter can be either medical or surgical. Known medical treatments include measures or medications that attempt to decrease acid secretion, increase gastric emptying or strengthen the LES. However, the medications are expensive and the measures typically have to be continued on a life long basis.
A more permanent treatment method for GERD can be performed surgically. Surgical methods attempt to strengthen the LES by incising the stomach and wrapping a portion of the stomach around the lower section of the esophagus. This technique is known as a fundoplication. However, surgical treatment requires longer post treatment care, increased pain and recovery time, as well as the associated risks with any surgical procedure.
The latest developments for treating GERD have attempted to provide a minimally invasive procedure to strengthen the lower esophageal area. One such treatment is disclosed by C. P. Swain et al., Knot Tying At Flexible Endoscopy, Gastrointestinal Endoscopy, 1994; 40:722-29, that calls for endoscopic sewing in the lower esophageal area. However the sewn portion of the esophagus in the Swain technique may relax again requiring further or alternate forms of treatment. Another technique disclosed by Donahue injects noxious, scarring substances into the lower esophageal area to create a fibrous reaction. P. E. Donahue, et. al., Endoscopic Ultrasonography Verifies Effect On Endoscopic Treatment Of Reflux In Dogs And Man, Surgical Endoscopy, 1993;7:524-28. However, the Donahue technique may require numerous and repeated injections.
The esophagus and LES are composed of three tissue layers; a mucosa or inner layer, a submucosa or middle layer, and a muscle or an outer layer. The submucosa layer is largely composed of collagen. It is well-known that heating of collagen tissue within an appropriate temperature range results in a tightening or shrinkage of the collagen tissue. However, there exists no known device or technique for strengthening the LES by shrinkage of collagen tissue as a means to treat GERD.